U.S. patent number 9,562,884 [Application Number 14/896,342] was granted by the patent office on 2017-02-07 for method for manufacturing no.sub.2 gas sensor for detection at room temperature.
This patent grant is currently assigned to Institute of Microelectronics, Chinese Academy of Sciences. The grantee listed for this patent is INSTITUTE OF MICROELECTRONICS, CHINESE ACADEMY OF SCIENCES. Invention is credited to Xin Chen, Dongmei Li, Shengfa Liang, Ming Liu, Changqing Xie, Shuang Zhan.
United States Patent |
9,562,884 |
Li , et al. |
February 7, 2017 |
Method for manufacturing NO.sub.2 gas sensor for detection at room
temperature
Abstract
A method for manufacturing an NO.sub.2 gas sensor for detection
at room temperature comprises: manufacturing a metal electrode on a
surface of a flexible substrate; manufacturing an SWCNTs/SnO.sub.2
sensitive film; and bonding the SWCNTs/SnO.sub.2 sensitive film
with a portion of the surface of the flexible substrate with the
metal electrode, so as to form the NO.sub.2 gas sensor for
detection at room temperature. The present disclosure solves the
problems of the poor adhesion between the sensitive material and
the flexible substrate, and a non-uniform distribution, and
achieves the purposes of secure bonding between the sensitive
material and the flexible substrate, and uniform distribution.
Inventors: |
Li; Dongmei (Beijing,
CN), Zhan; Shuang (Beijing, CN), Liang;
Shengfa (Beijing, CN), Chen; Xin (Beijing,
CN), Xie; Changqing (Beijing, CN), Liu;
Ming (Beijing, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
INSTITUTE OF MICROELECTRONICS, CHINESE ACADEMY OF SCIENCES |
Beijing |
N/A |
CN |
|
|
Assignee: |
Institute of Microelectronics,
Chinese Academy of Sciences (Beijing, CN)
|
Family
ID: |
52007413 |
Appl.
No.: |
14/896,342 |
Filed: |
June 5, 2013 |
PCT
Filed: |
June 05, 2013 |
PCT No.: |
PCT/CN2013/076761 |
371(c)(1),(2),(4) Date: |
December 04, 2015 |
PCT
Pub. No.: |
WO2014/194484 |
PCT
Pub. Date: |
December 11, 2014 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20160123944 A1 |
May 5, 2016 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N
27/12 (20130101); G01N 33/0037 (20130101); G01N
27/00 (20130101); G01N 33/0036 (20130101); Y02A
50/245 (20180101); Y02A 50/20 (20180101) |
Current International
Class: |
C03C
15/00 (20060101); G01N 33/00 (20060101); G01N
27/00 (20060101); G01N 27/12 (20060101) |
Field of
Search: |
;216/13,17,20,33,35,41 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
101824603 |
|
Sep 2010 |
|
CN |
|
102661981 |
|
Sep 2012 |
|
CN |
|
2006-162431 |
|
Jun 2006 |
|
JP |
|
WO 2011/146128 |
|
Nov 2011 |
|
WO |
|
Primary Examiner: Vinh; Lan
Attorney, Agent or Firm: Christensen Fonder P.A.
Claims
We claim:
1. A method for manufacturing an NO.sub.2 gas sensor for detection
at room temperature, comprising: manufacturing a metal electrode on
a surface of a flexible substrate; manufacturing an
SWCNTs/SnO.sub.2 sensitive film; and bonding the SWCNTs/SnO.sub.2
sensitive film with a portion of the surface of the flexible
substrate with the metal electrode to form the NO.sub.2 gas sensor
for detection at room temperature, wherein manufacturing the
SWCNTs/SnO.sub.2 sensitive film comprises: disproportionating CO
under a high pressure to generate a carbon nano tube, mixing the
carbon nano tube with an organic metal solution of 2-ethylhexanoate
and performing ultrasonic oscillation for 1.5 to 2.5 hours to
obtain a homogeneous mixed suspension liquid; then coating the
suspension liquid on a SiO.sub.2 base with spinning, dispensing,
dip-coating or screen printing and drying to evaporate solvent in a
suspension liquid coating; then calcining the SiO.sub.2 base for
which the solvent in the suspension liquid coating is evaporated to
obtain the SWCNTs/SnO.sub.2 sensitive film bonded with the
SiO.sub.2 base; and finally etching to remove the SiO.sub.2 base
with HF acid to separate the SWCNTs/SnO.sub.2 sensitive film from
the SiO.sub.2 base so as to obtain the SWCNTs/SnO.sub.2 sensitive
film.
2. The method according to claim 1, wherein bonding the
SWCNTs/SnO.sub.2 sensitive film with the portion of the surface of
the flexible substrate with the metal electrode to form the
NO.sub.2 gas sensor for detection at room temperature comprises:
coating a conductive silver paste layer on the portion of the
surface of the flexible substrate with the metal electrode, and
bonding the SWCNTs/SnO.sub.2 sensitive film with the portion of the
surface of the flexible substrate with the metal electrode using
the conductive silver paste to form the NO.sub.2 gas sensor for
detection at room temperature.
3. The method according to claim 1, wherein in calcining the
SiO.sub.2 base for which the solvent in the suspension liquid
coating is evaporated to obtain the SWCNTs/SnO.sub.2 sensitive film
bonded with the SiO.sub.2 base, a reaction equation when the
2-ethylhexanoate is calcined is as follows: ##STR00003##
4. The method according to claim 3, wherein the high temperature
calcination is performed at a temperature within 300-1000.degree.
C.
5. The method according to claim 1, wherein manufacturing the metal
electrode on the surface of the flexible substrate comprises:
cleaning the flexible substrate, coating photoresist on the surface
of the flexible substrate, and photoetching the photoresist to
remove photoresist formed at the metal electrode on the surface of
the flexible substrate so as to form an electrode pattern on the
surface of the flexible substrate; then depositing a Cr film and an
Au film in turn on the flexible substrate with the electrode
pattern using electron beam evaporation; and finally stripping the
photoresist and the Cr film and Au film on the photoresist, to form
the flexible substrate having the metal electrode on the surface
thereof.
6. The method according to claim 5, wherein the flexible substrate
comprises PI, PET or PEN.
7. The method according to claim 5, wherein the photoresist coated
on the surface of the flexible substrate is positive photoresist
comprising 9920 or 3220.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
This application is a U.S. national phase application of PCT
Application No. PCT/CN2013/076761 filed on Jun. 5, 2013, entitled
"MANUFACTURING METHOD OF NO.sub.2 GAS SENSOR FOR DETECTION AT ROOM
TEMPERATURE". This PCT Application is incorporated herein by
reference in its entirety.
TECHNICAL FIELD
The present disclosure relates to the field of gas sensor
technology, and in particular, to a method for manufacturing an
NO.sub.2 gas sensor for detection at room temperature.
BACKGROUND
With the development of science and technology, sensors are applied
widely, and it is imperative to manufacture sensors which are
portable and inexpensive and can be manufactured at a large scale.
Flexible substrate-based gas sensors essentially improve a lot of
problems due to many advantages such as flexibility thereof or the
like. Thereby, the flexible substrate-based gas sensors have a
broader application prospect.
NO.sub.2 belongs to typical atmospheric pollutants, and primarily
comes from burning of fossil fuel and automobile exhaust pollution.
NO.sub.2 is one of industrial pollutants which cause problems such
as acid rain, photochemical smog or the like, and causes
respiratory disease as it easily reacts with hydrocarbon in the
sunshine, which seriously threatens the health and survival of
human beings. With the rapid development of industries, people pay
more and more attention to monitoring of NO.sub.2. Researches on
NO.sub.2 gas sensors are a hotspot at home and abroad all the time.
In order to improve the sensitivity characteristics of the sensors,
people have put much effort on selection and modification of
material. With the rapid development of Internet of Things, sensors
with a portable design and low power consumption are widely
concerned. Therefore, it is a very important task to manufacture a
flexible NO.sub.2 gas sensor for detection at room temperature.
A conventional method for manufacturing a flexible NO.sub.2 gas
sensor for room temperature is to directly deposit a sensitive film
on a surface of a flexible substrate. In the process of
manufacturing a sensor, hygroscopic treatment is firstly performed
on the substrate, and then sensitive material is deposited on a
surface of the substrate using dip-coating, dispensing or
self-growing method. The sensitive film manufactured in this way
has a non-uniform thickness, and poor adhesion with the
substrate.
SUMMARY
Technical Problems to be Solved
The purpose of the present discourse is to provide a method for
manufacturing an NO.sub.2 gas sensor for detection at room
temperature, thereby solving the problems of the poor adhesion
between the sensitive material and the flexible substrate, and a
non-uniform distribution, and achieving the purposes of secure
bonding between the sensitive material and the flexible substrate,
and uniform distribution.
Technical Solutions
In order to achieve the above purposes, the present disclosure
provides a method for manufacturing an NO.sub.2 gas sensor for
detection at room temperature, comprising:
manufacturing a metal electrode on a surface of a flexible
substrate;
manufacturing an SWCNTs/SnO.sub.2 sensitive film; and
bonding the SWCNTs/SnO.sub.2 sensitive film with a portion of the
surface of the flexible substrate with the metal electrode to form
the NO.sub.2 gas sensor for detection at room temperature.
In the above solution, manufacturing the metal electrode on the
surface of the flexible substrate comprises:
cleaning the flexible substrate, coating photoresist on the surface
of the flexible substrate, and photoetching the photoresist to
remove photoresist formed at the metal electrode on the surface of
the flexible substrate to form an electrode pattern on the surface
of the flexible substrate; then depositing a Cr film and an Au film
in turn on the flexible substrate with the electrode pattern using
electron beam evaporation; and finally stripping the photoresist
and the Cr film and Au film on the photoresist, to form the
flexible substrate having the metal electrode on the surface
thereof.
In the above solution, the flexible substrate comprises PI, PET or
PEN.
In the above solution, the photoresist coated on the surface of the
flexible substrate is positive photoresist comprising 9920 or
3220.
In the above solution, manufacturing an SWCNTs/SnO.sub.2 sensitive
film comprises:
disproportionating CO under a high pressure to generate a carbon
nano tube, mixing the carbon nano tube with an organic metal
solution of 2-ethylhexanoate and performing ultrasonic oscillation
on them for 1.5 to 2.5 hours to obtain homogeneous mixed suspension
liquid; then coating the suspension liquid on the SiO.sub.2 base
with spinning, dispensing, dip-coating or screen printing and
drying to evaporate solvent in a suspension liquid coating; then
calcining the SiO.sub.2 base for which the solvent in the
suspension liquid coating is evaporated to obtain an
SWCNTs/SnO.sub.2 sensitive film bonded with the SiO.sub.2 base; and
finally etching to remove the SiO.sub.2 base with HF acid to
separate the SWCNTs/SnO.sub.2 sensitive film from the SiO.sub.2
base so as to obtain the SWCNTs/SnO.sub.2 sensitive film.
In the above solution, in calcining the SiO.sub.2 base for which
the solvent in the suspension liquid coating is evaporated to
obtain the SWCNTs/SnO.sub.2 sensitive film bonded with the
SiO.sub.2 base, a reaction equation when the 2-ethylhexanoate is
calcined is as follows:
##STR00001##
In the above solution, the high temperature calcination is
performed at a temperature within 300-1000.degree. C.
In the above solution, bonding the SWCNTs/SnO.sub.2 sensitive film
with the portion of the surface of the flexible substrate with the
metal electrode to form the NO.sub.2 gas sensor for detection at
room temperature comprises:
coating a conductive silver paste layer on the portion of the
surface of the flexible substrate with the metal electrode, and
bonding the SWCNTs/SnO.sub.2 sensitive film with the portion of the
surface of the flexible substrate with the metal electrode using
the conductive silver paste to form the NO.sub.2 gas sensor for
detection at room temperature.
Beneficial Effects
The method for manufacturing an NO.sub.2 gas sensor for detection
at room temperature according to the present disclosure avoids an
operation on the flexible substrate at a high temperature in the
process of manufacturing the sensitive film by bonding the material
of the sensitive film with the flexible substrate in an indirect
manner. This method comprises firstly coating an SWCNTs/SnO.sub.2
sensitive film on an SiO.sub.2 base, and then etching to remove the
SiO.sub.2 base using HF acid, to separate the SWCNTs/SnO.sub.2
sensitive film from the SiO.sub.2 base; and coating a conductive
silver paste layer on an electrode surface of the flexible
substrate to bond the sensitive film with the flexible substrate.
This method overcomes the problems of a non-uniform distribution of
the sensitive material and the poor adhesion between the sensitive
material and the flexible substrate for the sensitive film which is
manufactured with the conventional method using dip-coating,
dispensing or self-growing, and achieves a more uniform
distribution of the sensitive material on the surface of the
flexible substrate and enhances the adhesion between the sensitive
material and the flexible substrate by directly reacting on the
surface of the SiO.sub.2 base to generate sensitive material and
bonding the material of the sensitive film with the flexible
substrate in an indirect manner.
BRIEF DESCRIPTION OF THE DRAWINGS
For better illustrating the content of the present disclosure, the
present disclosure will be described in detail below in conjunction
with accompanying drawings and examples, wherein in the
accompanying drawings:
FIG. 1 is a flowchart of a method for manufacturing an NO.sub.2 gas
sensor for detection at room temperature according to the present
disclosure;
FIG. 2-1 is a diagram of a flexible substrate;
FIG. 2-2 is a diagram of coating photoresist on the flexible
substrate and forming an electrode pattern on the flexible
substrate;
FIG. 2-3 is a diagram after depositing a Cr film and an Au film on
the flexible substrate with an electrode pattern;
FIG. 2-4 is a diagram of stripping the photoresist and the Cr film
and the Au film thereon to obtain a flexible substrate with a metal
electrode;
FIG. 2-5 is a diagram of an SiO.sub.2 base;
FIG. 2-6 is a diagram of forming a sensitive film on the SiO.sub.2
base;
FIG. 2-7 is a diagram of an SWCNTs/SnO.sub.2 sensitive film which
is left after etching to remove a lower SiO.sub.2 base with HF
acid;
FIG. 2-8 is a diagram of coating a conductive silver paste layer on
a portion of the surface of the flexible substrate with the metal
electrode; and
FIG. 2-9 is a diagram of bonding the SWCNTs/SnO.sub.2 sensitive
film with the portion of the surface of the flexible substrate with
the metal electrode using the conductive silver paste.
DETAILED DESCRIPTION
In order to make the purposes, technical solutions, and advantages
of the present disclosure more clear and obvious, the present
disclosure will be further described in detail below in conjunction
with specific embodiments and with reference to accompanying
drawings.
The technical idea of the present disclosure is as follows:
disproportionating CO under a high pressure to generate a carbon
nano tube, mixing the carbon nano tube with an organic metal
solution of 2-ethylhexanoate and performing ultrasonic oscillation
on them for 1.5 to 2.5 hours (preferably, 2 hours) to obtain
homogeneous mixed suspension liquid; then coating the suspension
liquid on an SiO.sub.2 base in a manner such as spinning,
dispensing, dip-coating or screen printing and drying to evaporate
solvent in a suspension liquid coating; then calcining the
SiO.sub.2 base for which the solvent in the suspension liquid
coating is evaporated for 0.5 to 4 hours to obtain a composite
SWCNTs/SnO.sub.2 sensitive film; etching to remove lower SiO.sub.2
base with HF acid to separate the SWCNTs/SnO.sub.2 sensitive film
from the SiO.sub.2 base; and coating a conductive silver paste
layer on an electrode surface of the flexible substrate, and
bonding the sensitive film with the flexible substrate to form a
flexible NO.sub.2 gas sensor for detection at room temperature.
As shown in FIG. 1, FIG. 1 is a flowchart of a method for
manufacturing an NO.sub.2 gas sensor for detection at room
temperature according to the present disclosure. The method
comprises the following steps.
In a first step, a metal electrode is manufactured on a surface of
a flexible substrate.
In this step, firstly the flexible substrate is cleaned, as shown
in FIG. 2-1. The flexible substrate at least comprises PI, PET or
PEN or the like, has advantages such as portability, a low price,
and excellent flexibility or the like, and can extend the
application prospect of the sensors. Then, as shown in FIG. 2-2,
photoresist is coated on the flexible substrate. The photoresist
used herein is positive photoresist comprising 9920, 3220 or the
like. The photoresist is photoetched to remove photoresist formed
at the metal electrode on the flexible substrate to form an
electrode pattern on the flexible substrate. Then, as shown in FIG.
2-3, a Cr film and an Au film are deposited in turn on the flexible
substrate with an electrode pattern using electron beam evaporation
or other coating technology. Finally, as shown in FIG. 2-4, the
photoresist and the Cr film and Au film on the photoresist are
stripped, to form a flexible substrate with the metal electrode.
Other coating technology is magnetic sputtering, CVD, spinning,
screen printing or the like, with the purpose of depositing a
uniform film on the surface of the substrate.
In a second step, an SWCNTs/SnO.sub.2 sensitive film is
manufactured.
In this step, CO is disproportionated under a high pressure to
generate a carbon nano tube, the carbon nano tube is mixed with an
organic metal solution of 2-ethylhexanoate and ultrasonic
oscillation is performed on them for 1.5 to 2.5 hours (preferably,
2 hours) to obtain homogeneous mixed suspension liquid (this
process is merely a mixing process, without chemical reaction).
Then, the suspension liquid is coated on the SiO.sub.2 base in a
manner such as spinning, dispensing, dip-coating or screen
printing. The SiO.sub.2 base is shown in FIG. 2-5. Drying is
performed to evaporate solvent in a suspension liquid coating, and
then the SiO.sub.2 base for which the solvent in the suspension
liquid coating is evaporated is calcined for 0.5 to 4 hours at a
temperature within 300.degree. C.-1000.degree. C. to obtain an
SWCNTs/SnO.sub.2 sensitive film bonded with the SiO.sub.2 base, as
shown in FIG. 2-6. Etching is performed with HF acid to remove a
lower SiO.sub.2 base to separate the SWCNTs/SnO.sub.2 sensitive
film from the SiO.sub.2 base so as to obtain an SWCNTs/SnO.sub.2
sensitive film, as shown in FIG. 2-7.
In the process of calcining the SiO.sub.2 base for which the
solvent in the suspension liquid coating is evaporated to obtain an
SWCNTs/SnO.sub.2 sensitive film bonded with the SiO.sub.2 base, a
reaction equation when the 2-ethylhexanoate is calcined to
manufacture SnO.sub.2 is as follows:
##STR00002##
In a third step, the SWCNTs/SnO.sub.2 sensitive film is bonded with
a portion of the surface of the flexible substrate with the metal
electrode to form an NO.sub.2 gas sensor for detection at room
temperature.
In this step, as shown in FIG. 2-8, a conductive silver paste layer
is coated on the portion of the surface of the flexible substrate
with the metal electrode. As shown in FIG. 2-9, the
SWCNTs/SnO.sub.2 sensitive film is bonded with the portion of the
surface of the flexible substrate with the metal electrode using
the conductive silver paste to obtain the NO.sub.2 gas sensor for
detection at room temperature. The NO.sub.2 gas sensor can have
better sensitivity for detecting NO.sub.2 at room temperature.
It can be seen from the above embodiments that the method for
manufacturing an NO.sub.2 gas sensor for detection at room
temperature according to the present disclosure avoids an operation
on the flexible substrate at a high temperature in the process of
manufacturing the sensitive film by bonding the material of the
sensitive film with the flexible substrate in an indirect manner,
overcomes the problems of a non-uniform distribution of the
sensitive material and the poor adhesion between the sensitive
material and the flexible substrate or the like for the sensitive
film which is manufactured with the conventional method using
dip-coating, dispensing or self-growing, and achieves a more
uniform distribution of the sensitive material on the surface of
the flexible substrate and enhances the adhesion between the
sensitive material and the flexible substrate by directly reacting
on the surface of the SiO.sub.2 base to generate sensitive material
and bonding the material of the sensitive film with the flexible
substrate in an indirect manner.
The purposes, technical solutions and beneficial effects of the
present disclosure are further described in detail in the specific
embodiments described above. It should be understood that the above
description is merely specific embodiments of the present
disclosure, and is not intended to limit the present disclosure.
Any amendment, equivalent substitution, improvement or the like,
which is made within the spirit and principle of the present
disclosure, should be included in the protection scope of the
present disclosure.
* * * * *